The present invention relates to an image forming apparatus that forms an image based on image data, and transfers the image onto a paper sheet, so as to conduct a printing operation.
An image forming apparatus forms an image based on image data onto a photoreceptor drum, and transfers the image onto a paper sheet directly or through an intermediate transfer belt. Concretely speaking, when forming the image, the image forming apparatus forms a latent image onto the photoreceptor drum through the exposing process including steps of uniformly charging the photoreceptor drum, and irradiating light, which is emitted from a laser diode or the like, and the intensity of which is modulated on the basis of the image data, onto the photoreceptor drum. Successively, the latent image formed on the photoreceptor drum is developed with toner, fed from a developing section, so as to form a toner image thereon. Still successively, the concerned toner image is directly transferred onto the paper sheet at a transferring section, or the concerned toner image is primarily transferred onto the intermediate transfer belt, and then, the toner image transferred onto the intermediate transfer belt is further transferred onto the paper sheet at a secondary transferring section. After the transferring operation has been completed, a cleaning section removes residual toner remaining on the photoreceptor drum from the circumferential surface thereof, and further, a discharging section discharges the residual electric potential still residing on the circumferential surface of the photoreceptor drum, so as to prepare for the next image forming operation.
In the image forming apparatus as abovementioned, since the printing operation is achieved by transferring the toner image, formed on the photoreceptor drum, onto the paper sheet as its final step, if a certain abnormality, such as a scar or the like, resides on the photoreceptor drum, an abnormal image would be transferred onto the paper sheet, and accordingly, sometimes, it would become difficult to obtain a good printing result.
To cope with such the drawback, for instance, Tokkaihei 7-55710 (Japanese Patent Application Laid-Open Publication) sets forth a defect inspection apparatus that detects a surface defect, such as a scar or the like, generated on the circumferential surface of the photoreceptor drum currently manufactured. The defect inspection apparatus concerned includes: a light source to irradiate a light onto the photoreceptor drum in a direction of the circumferential surface axis thereof, a line sensor that receives a reflected light reflected from the irradiation surface so as to detect the intensity of the reflected light; and a signal processing section to process the signal outputted from the line sensor; so as to make it possible to detect the defect by focusing a bright image section and a dark image section, formed on the circumferential surface of the photoreceptor drum, onto the line sensor.
Further, in order to detect a deterioration of the charging device, Tokkaihei 7-191580 (Japanese Patent Application Laid-Open Publication) sets forth an electro-photographic type recording apparatus that is provided with: a line sensor that is disposed downstream the developing device so as to read a visual image residing on the circumferential surface of the photoreceptor drum located upstream the charging device; a detecting section that processes a signal read by the line sensor so as to detect an abnormal visual image; and an abnormal visual-image detection control section.
Still further, recently, since the toner, which is to be employed by the image forming apparatus, tends to be increasingly finer than ever in conjunction with the trend of achieving a high quality of the reproduced image, it becomes difficult to maintain the cleaning efficiency over a long term. On the other hand, in order to suppress a cost for a unit printing, it has been desired that the time for exchanging the cleaning section be made to delay later, so as to use the concerned cleaning section as longer as possible. In addition, in the conventional practice, the exchange time has been set at a predetermined timing (in conformity with the PM (Parts Management) cycle), or at such a time when a certain defects has appeared before the predetermined timing arrives, though the duration time (durable term) of the cleaning section depends on environmental factors. Accordingly, there has been desired such a system that makes it possible not only to maintain the cleaning efficiency as longer as possible, but also to suppress the wasted exchange of the cleaning section. Further, in such a image forming apparatus that is provided with the cleaning mechanisms in regard to both the intermediate transfer member and the secondary transferring member, there has arisen another problem that it takes much time for specifying a portion where the cleaning deficiency currently occurs.
Conventionally, Tokkai 2009-199036 (Japanese Patent Application Laid-Open Publication) sets forth a residual toner inspection apparatus that inspects the cleaning efficiency of the photoreceptor member abovementioned. The residual toner inspection apparatus concerned is provided with: a laser beam irradiating section to irradiate a laser beam in parallel onto an area in the vicinity of the viewing surface of the photoreceptor member concerned; and an observing section to observe scattering light generated by the abovementioned laser beam on the circumferential surface of the photoreceptor member.
However, since the defect inspection apparatus set forth in Tokkaihei 7-55710 conducts the inspection of the manufactured photoreceptor member before the photoreceptor member concerned is installed into the image forming apparatus, it is impossible to detect the scars or the like, which have been generated over time on the circumferential surface of the photoreceptor member.
Further, since the apparatus set forth in Tokkaihei 7-191580 detects a deterioration of the charging device by viewing a visual image, it is impossible to evaluate the cleaning efficiency.
Still further, since the residual toner inspection apparatus set forth in Tokkai 2009-199036 conducts the operation for evaluating the cleaning member of the image forming apparatus before the cleaning member concerned is installed into the image forming apparatus, it is impossible to evaluate the efficiency deteriorations of the cleaning member, which have been caused by the image forming cycles repeatedly conducted over time in the image forming apparatus concerned. In this connection, although the Tokkai 2009-199036 also sets forth that the residual toner inspection apparatus may be installed into an actual image forming apparatus, it would be practically difficult (or virtually impossible) to install the concerned apparatus into the actual image forming apparatus from a special factor and a cost effective points of view, since the observing operation is achieved by shifting the CCD (Charge Coupled Device) imager to be included in the observation section in an axis direction of the photoreceptor member (photoreceptor drum).